AsianScientist (Mar. 9, 2016) – Japanese researchers have proposed a design for a submerged marine turbine to harness the energy of the Kuroshio current flowing along the Japanese coast. Their work was published in the journal Renewable Energy.
It is becoming increasingly clear that our future cannot be based on fossil fuels, if only because they are a finite resource; and we are very close to exhausting them.
While solar and wind power is often seen as the main locomotive of the energy revolution, they alone cannot provide all the energy we need, especially considering that energy consumption around the world is steadily growing.
Due to day-night cycles and seasonal weather patterns, solar and wind power is inherently intermittent. Moreover, utility-scale power farms require vast tracts of land.
Ocean currents are an alternative source of power, comparable to fossil fuels in terms of consistency and reliability, and yet at the same time, clean and renewable. Ocean currents are rather slow, but as water is over 800 times as dense as air, even a slow current contains energy comparable to a strong wind. Additionally, currents do not stop or change direction.
The turbine design, by researchers at the Quantum Wave Microscopy Unit at Okinawa Institute of Science and Technology Graduate University (OIST), is especially suitable for regions regularly devastated by storms and typhoons, such as Japan, Taiwan and the Philippines.
The turbine operates in the middle layer of the current, 100 meters below the surface, where the waters flow calmly and steadily even during strong storms. It comprises of a minimal number of components, essential for easy maintenance, low costs, and a low failure rate.
The turbine design can be described as a hybrid of a kite and a wind turbine: an ocean-current turbine is anchored to seabed with a line and floats in the current while water rotates its three blades. The device can easily be scaled up or down, depending on local conditions and needs.
The team also built a prototype turbine and conducted various experiments to test its design and configuration. Results confirmed the robustness and stability of the turbine construction, showing that the achieved efficiency is comparable to that of commercial wind turbines.
“Our design is simple, reliable, and power-efficient,” says corresponding author Dr. Katsutoshi Shirasawa, a staff scientist in the Quantum Wave Microscopy Unit.
Shirasawa and his colleagues aspire to build an energy farm featuring 300 turbines and 80 meters in diameter. The expected output is about 1 GW—the equivalent of a nuclear reactor and capable of powering over 400,000 homes. This project will be an important step towards development of green energy.
The article can be found at: Shirasawa et al. (2016) Experimental Verification of a Floating Ocean-current Turbine with a Single Rotor for Use in Kuroshio Currents.
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Source: Okinawa Institute of Science and Technology Graduate University; Photo: Tony Hisgett/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.
